Refractive index and formaldehyde sensing with silver nanocubes

Area of Science:

• Materials Science
• Nanotechnology
• Analytical Chemistry

Background:

• Silver nanocubes are promising nanomaterials for optical sensing due to their unique plasmonic properties.
• Developing efficient synthesis methods for controlled silver nanocube formation is crucial for their application.
• Accurate detection of analytes like glucose and formaldehyde is important in environmental and food safety.

Purpose of the Study:

• To synthesize silver (Ag) nanocubes using a sodium sulfide-assisted solvothermal method.
• To investigate the refractive index sensitivity of the synthesized Ag nanocubes for glucose detection.
• To evaluate the formaldehyde detection capability of Ag nanocubes in water and milk samples.

Main Methods:

• Solvothermal synthesis assisted by sodium sulfide to produce Ag nanocubes with controlled edge lengths (32 and 44 nm) at 145-155 °C.
• Measurement of refractive index sensitivity using aqueous glucose solutions, determining sensitivity in colloidal dispersion (161 nm/RIU) and on an LSPR chip (116 nm/RIU).
• Formaldehyde detection utilizing the interaction between immobilized 4-aminothiophenol on Ag nanocubes and formaldehyde, with sensitivity measured in water (0.62 nm/µM) and diluted milk (0.29 nm/µM).

Main Results:

• Successfully synthesized Ag nanocubes with edge lengths of 32 nm and 44 nm via a sodium sulfide-assisted solvothermal route.
• Achieved high refractive index sensitivity of 161 nm/RIU in colloidal dispersion and 116 nm/RIU on an LSPR chip.
• Demonstrated formaldehyde detection with sensitivities of 0.62 nm/µM in water and 0.29 nm/µM in diluted milk.

Conclusions:

• The sodium sulfide-assisted solvothermal method provides a viable route for synthesizing Ag nanocubes suitable for sensing applications.
• Synthesized Ag nanocubes exhibit excellent refractive index sensitivity, making them effective for glucose detection.
• The developed Ag nanocube-based system demonstrates promising capabilities for detecting formaldehyde in real-world samples like water and milk.